Paper is normally produced by continuous machines which, through the delivery of a stock of cellulose fibers and water distributed from headboxes, generate a ply of cellulose material on a forming fabric, which ply is dried and wound in reels of large diameter. These reels are subsequently unwound and rewound to form logs of smaller diameter. The logs are subsequently divided into rolls of dimensions equal to the dimension of the end product. With this technique, rolls of toilet paper, kitchen towels or other tissue paper products are normally manufactured.
Rewinding machines are used to produce convolutely wound rolls or “logs” of web material. Rewinders are used to convert large parent rolls of paper into retail sized rolls and bathroom tissue and paper towels. These rewinding machines typically wind a predetermined length of web material about a tubular winding core normally made of cardboard. These rolls or logs are then cut into a plurality of smaller-size rolls intended for commercial sale and consumer use. The tubular winding core section remains inside each convolutely wound roll of web material. In both cases the end product contains a tubular core made of material different from that forming the roll.
One type of rewinding machine, known as a surface rewinding machine (or surface winder), the rotational movement of the tubular core on which the roll or log is formed is provided by peripheral members in the form of rollers or rotating cylinders and/or belts with which the roll or log is kept in contact during formation. Exemplary surface winders are disclosed in U.S. Pat. Nos. 3,630,462; 3,791,602; 4,541,583; 4,723,724; 4,828,195; 4,856,752; 4,909,452; 4,962,897; 5,104,155; 5,137,225; 5,226,611; 5,267,703; 5,285,979; 5,312,059; 5,368,252; 5,370,335; 5,402,960; 5,431,357; 5,505,405; 5,538,199; 5,542,622; 5,603,467; 5,769,352; 5,772,149; 5,779,180; 5,839,680; 5,845,867; 5,909,856; 5,979,818; 6,000,657; 6,056,229; 6,565,033; 6,595,458; 6,595,459; 6,648,266; 6,659,387; 6,698,681; 6,715,709; 6,729,572; 6,752,344; 6,752,345; and 6,866,220; the following International applications also provide exemplary surface winders; International Publication Nos. 01/16008 A1; 02/055420 A1; 03/074398 A2; 99/02439; 99/42393; and EPO Patent Application No. 0514226 A1.
The surface winder is comprised of 3 principle winding rolls to perform the surface winding process. These rolls are the first winding roller (or upper winding roll (UWR)), the second winding roller (or lower winding roll (LWR)), and the third winding roller (or rider roll (RR)). The respective rolls are named due to where or how they contact a winding log. The UWR and LWR contact the winding log on the upper and lower portions respectively and the RR “rides” on the upper portion of the winding log as it increases in diameter as web material is wound thereabout. The winding log enters the surface winder and is adhesively attached to a web material to be wound thereabout in a region of compression disposed between the UWR and LWR. The winding log is initially rotated by the UWR in a region disposed between the UWR and a stationary core cradle and rotationally translates to a region disposed intermediate the rotating, but stationary, UWR and LWR (known as the winding nest region). The RR contacts the surface of the rotating winding log in the winding nest region and translates away from the UWR and LWR as web material continues to be convolutely wound about the winding log.
In an exemplary surface wind system, a web material is convolutely wound about a paperboard core of 1.5″ to 1.7″ diameter and of a length that corresponds to the width of the tissue parent roll which comes from the paper machine, usually in width from 65″ to 155″.
However useful, current surface winders do have limitations. For example, the core, prior to being inserted into the winding system, will typically have an adhesive disposed upon it. This adhesive is intended to contact the web material coming into the UWR and cause it to fixably attach to the core via the adhesive disposed thereupon. This attachment of the web material to the core via the core glue is sometimes referred to as core bonding.
The core having the adhesive disposed upon its surface is then transferred to the surface winding system. However, there are several degrees of freedom with such a system as the core glue is applied to the core, the core is transferred to the winding cradle and then a portion of the web material is then adhesively attached to the core. These numerous degrees of freedom provide a significant opportunity for misalignment, mis-attachment, mis-insertion, etc. of the web material to the adhesive-laden core with such a system.
For example, as shown in FIG. 1, when a core is inserted into the region between the UWR and the cradle prior to insertion into the winding nest area, the core must undergo a transformation where the core surface speed must be accelerated from zero (i.e., has no surface speed at the point of entry) to the surface speed of the UWR (i.e., UWR running speed). In other words, the surface speed of the core is accelerated from zero to the surface speed of the UWR while disposed within the region between the cradle and the UWR. However, it has been observed that several mechanics-related principles in this region of the re-winder act to retard this required surface speed acceleration.
First, the entry portion of the cradle positioned at a fixed point disposed orbitally about the UWR typically has a smooth surface. An exemplary entry point is shown in FIG. 2. The placement of core having zero surface speed into the entry point of the winding cradle and the ensuing contact with the web material in contact with the UWR causes the core to slip (i.e., not spin) against this initial portion of the winding cradle. This slippage is represented by the arrow labeled “S” in FIG. 3. This slippage is believed to cause the core to oblongly deform into an ellipsoid shape.
Second, the glue-laden core is targeted to contact the web material in contact with the UWR at a predetermined location. Typically the targeted location on the web is immediately adjacent a perforation. If this targeted attachment location changes, several unfavorable results can occur in the early stage formation of the wound material.
For example, if the web attachment point occurs at a point removed backwards from the region near the perforation (e.g., behind the perforation), any excess leading web material will ‘fold-back’ upon the core and overlap the region of actual attachment of the web material to the core. This causes a consumer undesirable and unattractively wound product.
If the web attachment point occurs at a point removed forwards from the region near the perforation (e.g., ahead of the perforation), the web material can fail to attach to the core. This can result in the deposition of the adhesive disposed upon the core material to contact the manufacturing equipment. Ultimately, this can result in a process shut-down. Not only will the web material need to be re-threaded though the converting equipment, but adhesive will also have to be removed from the surfaces of the rewinding equipment such as the winding cradle and UWR.
Finally, if the core slides through the initial portion of the winding cradle, the adhesive disposed upon the core can be deposited upon the surfaces of the re-winding equipment (e.g., the winding cradle and UWR). This is a significant manufacturing issue that can result in a process shut-down to remove adhesive from the surfaces of the rewinding equipment such as the winding cradle and UWR.
Thus, there is a clearly defined need to improve the correlation and placement of adhesive upon a core at a point that is closer to the point of insertion into the winding cradle to prevent the drawbacks observed by current surface winding equipment that meets current manufacturing financial and processing targets. This can provide a closer association of the position upon the core where the adhesive is disposed thereupon with the web material that is intended to be contacted thereto.